In general, the result of orthodontic treatment is not stable. After active treatment, changes can occur as a result of a number of biological processes. The application of retention aims to counteract such changes and thereby preserve the result of orthodontic treatment. The way practitioners design the retention phase varies considerably. To reduce undesired variation in orthodontic retention between practices and to improve quality of care, clinical practice guidelines for retention were developed by the Dutch Association of Orthodontists. These guidelines contain recommendations for the application of retention. The duration of retention, additional techniques and retention after treatment of Class II malocclusions are discussed; consensus has not yet been reached on these subjects.